[ibr-168-ae]-Document level allowances (IBG-20) with Document level allowance VAT category code (IBT-095) as 'Exempt from VAT' MUST have a Document level allowance VAT exemption reason code (IBT-196)
ibr-168-ae
cac:AllowanceCharge[cbc:ChargeIndicator = false()]
not(cac:TaxCategory/cbc:ID = "E" and not(exists(cbc:AllowanceChargeReasonCode)))